Time Slip Ichimannen: Prime Rose

An emergency arises on Earth when a space fortress known as Death Mask splits up and starts falling toward the cities of Kujukuri and Dallas, forcing their people to evacuate. When the fragments make contact with the surface, the two areas suddenly vanish—and go 10 thousand years into the future.

Even though he refuses to believe such an event, Gai Tanbara is sent to investigate the phenomenon. Upon arriving in the future Kujukuri Beach, he finds only desert, ruins, and aggressive life forms at first. However, after rescuing a girl named Emiya Tachi, Gai ends up captive in a labor camp. When he discovers that the Death Mask is behind the camps, Gai must find a way to stop the oppression for good with the help of Emiya, who has her own reason for vengeance.